Question

Assume that you have a solution of 0.1 M glucose 6-phosphate. To this solution, you add the enzyme phosphoglucomutase, which catalyzes the following reaction:

Glucose 6-phosphate ? glucose 1-phosphate

The ?G

Answer 1

(a) delta G= -RT ln Keq
+1.8 5 2(1.98 3 1023 kcal21 K21 mol21) (298 K)
(ln[G1P]y[G6P])
-3.05 5 ln [G1P]y[G6P]
+3.05 5 ln [G6P]y[G1P]
Keq-1=21 or Keq= 4.8 X 10^-2
Because [G6P]/[G1P]= 21, there is 1 molecule of G1P for every 21 molecules of G6P. Because we started with 0.1 M, the [G1P] is 1/22(0.1 M)= 0.0045 M and [G6P] must be 21/22(0.1 M) or 0.096 M. Consequently, the reaction does not proceed as written to a significant extent.
(b) Supply G6P at a high rate and remove G1P at a high rate by other reactions. In other words, make sure that the [G6P]/[G1P] is kept large.